1. Technical Field
The present invention relates to a D-D portable neutron generator apparatus using prompt gamma-ray neutron activation analysis (PGNAA) comprising a portable neutron generator, a high density polyethylene (HDP) cylinder, a cylindrical gamma ray detector, a lead shield, and a neutron shield.
2. Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
The prompt gamma-ray neutron activation analysis (PGNAA) technique is widely used for in situ elemental analysis of bulk samples in several scientific disciplines including environmental, industrial, and health sciences (R. L. Paul and R. M. Lindstrom, “Prompt gamma-ray activation analysis: fundamentals and applications,” Journal of Radioanalytical and Nuclear Chemistry, vol. 243, no. 1, pp. 181-189, 2000 incorporated herein by reference in its entirety). Its area of application ranges from quality-control tasks in mining and environmental (D. L. Chichester, J. D. Simpson, and M. Lemchak, “Advanced compact accelerator neutron generator technology for active neutron interrogation field work,” Journal of Radioanalytical and Nuclear Chemistry, vol. 271, no. 3, pp. 629-637, 2007; Z. Idiri, H. Mazrou, A. Amokrane, and S. Bedek, “Characterization of an Am—Be PGNAA set up developed for in situ liquid analysis: application to domestic waste water and industrial liquid effluents analysis,” Nuclear Instruments and Methods in Physics Research B, vol. 268, no. 2, pp. 213-218, 2010; A. A. Naqvi, M. S. Al-Anezi, Z. Kalakada et al., “Response tests of a LaCl3:Ce scintillation detector with low energy prompt gamma rays from boron and cadmium,” Applied Radiation and Isotopes, vol. 70, no. 5, pp. 882-887, 2012; A. A. Naqvi, Z. Kalakada, M. S. Al-Anezi et al., “Low energy prompt gamma-ray tests of a large volume BGO detector,” Applied Radiation and Isotopes, vol. 70, no. 1, pp. 222-226, 2012—each incorporated herein by reference in its entirety) and building construction industries (R. A. Livingston, M. Al-Sheikhly, and A. B. Mohamed, “Numerical simulation of the PGNA signal from chlorine diffusion gradients in concrete,” Applied Radiation and Isotopes, vol. 68, no. 4-5, pp. 679-682, 2010—incorporated herein by reference in its entirety) to contraband detection for homeland security in concealed containers (A. Buffler and J. Tickner, “Detecting contraband using neutrons: challenges and future directions,” RadiationMeasurements, vol. 45, no. 10, pp. 1186-1192, 2010; E. H. Seabury, “PINS measurements of explosive stimulants for cargo screening,” Report no. INL/EXT-08-14053, Idaho National Laboratory, Idaho Falls, Id., USA, 2008; E. H. Seabury, J. C. Wharton, and A. J. Caffrey, “Response of a LaBr3:Ce detector to 2 11 MeV gamma rays,” Report no. INL/CON-06-11300, Idaho National Laboratory, Idaho Falls, Id., USA, 2006; E. H. Seabury and A. J. Caffrey, “Explosive detection and identification by PGNAA,” Report no. INEEL/EXT-04-02475, Idaho National Laboratory, Idaho Falls, Id., USA, 2004; D. Strelllis and T. Gozani, “Classifying threat with a 14 MeV neutron interrogation system,” Applied Radiation and Isotopes, vol. 63, no. 5-6, pp. 799-803, 2005—each incorporated herein by reference in its entirety). Prompt gamma rays can be excited in samples via thermal neutron capture (nth, γ) reaction and fast neutron inelastic scattering (n, nγ) reactions.
Former reaction is used for elements with appreciable thermal neutrons capture cross-sections, while later reaction is used for elements with negligible thermal neutron capture cross-section. Therefore prompt gamma rays produced via 14 MeV neutron inelastic scattering from elements are used to measure C, N, and O concentrations in bulk samples (P. A. Dokhale, J. Csikai, and L. Ol^Ah, “Investigations on neutron-induced prompt gamma ray analysis of bulk samples,” Applied Radiation and Isotopes, vol. 54, no. 6, pp. 967-971, 2001; P. A. Dokhale, J. Csikai, and L. Ol^Ah, “Investigations on neutron-induced prompt gamma ray analysis of bulk samples,” Applied Radiation and Isotopes, vol. 54, no. 6, pp. 967-971, 2001; C. Eleon, B. Perot, C. Carasco, D. Sudac, J. Obhodas, and V. Valkovic, “Experimental and MCNP simulated gamma-ray spectra for the UNCOSS neutron-based explosive detector,” Nuclear Instruments and Methods in Physics Research A, vol. 629, no. 1, pp. 220-229, 2011; A. V. Kuznetsov, A. V. Evsenin, I. Y. Gorshkov, O. I. Osetrov, and D. N. Vakhtin, “Detection of buried explosives using portable neutron sources with nanosecond timing,” Applied Radiation and Isotopes, vol. 61, no. 1, pp. 51-57, 2004; A. A. Naqvi, F. A. Al-Matouq, F. Z. Khiari, A. A. Isab, Khateebur-Rehman, and M. Raashid, “Prompt gamma tests of LaBr3:Ce and BGO detectors for detection of hydrogen, carbon and oxygen in bulk samples,” Nuclear Instruments and Methods in Physics Research A, vol. 684, pp. 82-87, 2012; B. Perota, C. Carasco, S. Bernard et al., “Measurement of 14 MeV neutron-induced prompt gamma-ray spectra from 15 elements found in cargo containers,” Applied Radiation and Isotopes, vol. 66, no. 4, pp. 421-434, 2008—each incorporated herein by reference in its entirety). Due to interference of weak intensity nitrogen prompt gamma rays with oxygen gamma rays, detection of nitrogen in bulk samples is a tedious task in 14 MeV neutron inelastic scattering studies. In spite of small thermal neutron capture cross-section, nitrogen can also be detected via prompt gamma ray studies in thermal neutron capture reaction studies (A. Favalli, H.-C. Mehner, V. Ciriello, and B. Pedersen, “Investigation of the PGNAA using the LaBr3 scintillation detector,” Applied Radiation and Isotopes, vol. 68, no. 4-5, pp. 901-904, 2010; A. T. Farsoni and S. A. Mireshghi, “Design and evaluation of a TNA explosive-detection system to screen carry-on luggage,” Journal of Radioanalytical and Nuclear Chemistry, vol. 248, no. 3, pp. 695-697, 2001—each incorporated herein by reference in its entirety). Conventionally, nitrogen detection in bulk sample via thermal neutron capture is carried out using a 252Cf neutron source.